Chartbook on Disability in New York State, 1998 - 2000

Appendix A

Data Source

The Behavioral Risk Factor Surveillance System (BRFSS) is a telephone survey limited to the noninstitutionalized, civilian adult (aged 18 years and older) population. The system monitors modifiable risk behaviors and other factors contributing to the leading causes of morbidity and mortality in the population. BRFSS data are useful for planning, initiating, and supporting health promotion and disease prevention programs at state and federal levels, and for monitoring progress toward achieving health objectives for the state and nation. The New York State Department of Health (NYSDOH) has administered the BRFSS survey annually since 1985, and since 1993 has collected information on activity limitations. From 1998 to 2000, the NYS BRFSS included a special Disability Module, which contained items to identify respondents with disabilities and to assess the nature and degree of those disabilities. Also included as part of the module were five "healthy days" items, which asked respondents to quantify the number of recent (past month) days of impaired health.


Disability and other health-related questions were asked of 8,538 respondents in New York State over the period 1998-2000. Data were weighted to adjust for the selection probabilities and the estimates of age-sex-race distribution of adults in the state. The sample size resulted in estimates for a weighted population of 45,558,133 persons, a yearly average of 13,852,711 over the three-year period.

Assessment of Disability

For the purposes of this chartbook, the definition of "disability" was based on responses to four items that were part of the BRFSS Disability Module from 1998 to 2000:

  • "Are you limited in the kind or amount of work you can do because of any impairment or health problem?"
  • "Because of any impairment or health problem, do you have any trouble learning, remembering, or concentrating?"
  • "If you use special equipment or help from others to get around, what type do you use?"
  • "Are you limited in any way in any activities because of any impairment or health problem?"

The responses to the four disability screener questions are presented in Table A-1. As noted, the percentage of respondents reporting a health-related work limitation (15.8%) was similar to that for any health-related activity limitation (15.0%). Overall, 22.5% of the respondents gave an affirmative response to at least one of the four screener questions.

A negative response to all four items assigned the respondent to the group of persons with no disabilities (No Disability). An affirmative response to at least one of these four items identified the respondent as a person with a disability, and follow-up questions were asked to further assess the respondent’s limitation status:

  • "Because of any impairment or health problem, do you need the help of other persons with your personal care needs, such as eating, bathing, dressing, or getting around the house?"
  • "Because of any impairment or health problem, do you need the help of other persons in handling your routine needs, such as everyday household chores, doing necessary business, shopping, or getting around for other purposes?"

Table A-1. Responses of New York Adults to Disability Screener Questions: 1998-2000 BRFSS

Screener Question No. Weighted Percentage of "Yes" Responses
Work limitation 1,323 15.8
Learning difficulty 559 6.5
Need for special equipment 406 4.9
Any activity limitation 1,275 15.0

Any disability



An affirmative response to either or both of these items classified the respondent as a person with a greater degree of disability (Disability/Help), whereas a negative response to both questions identified the respondent as having a lesser degree of disability (Disability/No Help). These three categories of disability status (Disability/Help, Disability/No Help, No Disability) served as the comparison groups throughout the chartbook.

Responses to the four screener items by disability subgroup are presented in Table A-2. With one exception (difficulty in learning), the proportion of respondents reporting each particular type of limitation was significantly greater in the subgroup requiring assistance. The greatest difference between the subgroups was in the proportions reporting the need for special equipment or help from others to get around, as 45.4% of those needing assistance identified this need, compared to only 13.5% of the subgroup needing no help. Within subgroups, respondents were equally as likely to report a health-related work limitation and any healthrelated activity limitation. The responses among those needing assistance were 88.8% and 84.2%, respectively.

Table A-2. Type of Limitation Reported, by Disability Subgroup: 1998-2000 BRFSS

Screener Question Disability
No Help Help
No. % (95% CI) No. % (95% CI)
Work limitation 881 63.9 (61.0-66.8) 442 88.8 (85.8-91.8)
Learning difficulty 391 27.4 (24.7-30.1) 168 32.8 (28.1-37.6)
Need for special eqipment 186 13.5 (11.4-15.6) 220 45.4 (40.3-50.5)
Any activity limitation 847 60.5 (57.5-68.4) 428 84.2 (80.2-88.2)
Note: Percentages add to more than 100% within subgroups because respondents could answer "yes" to more than one question.

Data Analysis

As a preliminary step, annual (1998-2000) prevalence estimates were computed for the three disability subgroups within sociodemographic categories [see Appendix C] and examined for trends. Item responses of "don’t know/not sure" and "refused" were treated as missing values. Persons for whom responses to all four items were missing were excluded from the analyses. This resulted in the exclusion of responses from 234 persons (2.7% of the total sample). Data from 1998, 1999, and 2000 were then combined for further analysis in order to increase the precision of prevalence estimates. The distribution of disability across selected sociodemographic, health status, chronic condition, and risk factor subgroups was assessed by generating weighted point estimates of proportions and 95% confidence intervals, which indicate the precision of the estimates and permit assessment of subgroup differences. If the resulting lower bound of a confidence interval was a negative number, it was reported as 0.0. All estimates and associated standard errors were generated using SAS-callable SUDAAN software (PROC CROSSTAB procedure),24 which accounted for the multistage, stratified sampling of the survey.

Age Adjustment (Age Standardization)

The data on prevalence of chronic conditions and health risk factors [see Tables B-9, B-10, and B-11] were age adjusted to allow comparison among the disability subgroups, which have different age structures [see Figure 2 and Table B-1]. The direct method of adjustment was used, with the weighted age distribution of the NYS BRFSS for the designated year or years serving as the standard population.


Findings based on the BRFSS survey are subject to several limitations. The BRFSS does not sample persons less than 18 years old, thus the findings might underestimate the true prevalence of disability in New York State. The BRFSS excludes persons without telephones. The survey represents undocumented self-reported data; self-reported indicators of activity limitation have not been validated as measures of disability. The case definition questions used in this analysis do not account for duration of disability. Persons not included are those whose health condition would not permit a telephone interview, for example, those who are hearing impaired; have cognitive, speech, and other communication impairments; have limited physical stamina; or could not get to the telephone.25 Lastly, response rates for the NYS BRFSS declined in each subsequent survey year. Although the weighting procedure controls for nonresponse, caution should be exercised in the interpretation of results because missing data from nonparticipants might vary from those provided by survey respondents.25

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